On Wed, Sep 27, 2023 at 11:28 PM Richard Biener via Fortran <fort...@gcc.gnu.org> wrote: > > On Wed, Sep 27, 2023 at 11:48 PM Jeff Law via Fortran > <fort...@gcc.gnu.org> wrote: > > > > > > > > On 9/27/23 12:21, Toon Moene wrote: > > > > > > > > The lto-ing of libgfortran did succeed, because I did get a new warning: > > > > > > gfortran -O3 -flto -flto-partition=none -static -o xlintstrfz zchkrfp.o > > > zdrvrfp.o zdrvrf1.o zdrvrf2.o zdrvrf3.o zdrvrf4.o zerrrfp.o zlatb4.o > > > zlaipd.o zlarhs.o zsbmv.o zget04.o zpot01.o zpot03.o zpot02.o chkxer.o > > > xerbla.o alaerh.o aladhd.o alahd.o alasvm.o ../../libtmglib.a > > > ../../liblapack.a ../../librefblas.a > > > In function 'xtoa_big', > > > inlined from 'write_z' at > > > /home/toon/compilers/gcc/libgfortran/io/write.c:1296:11, > > > inlined from 'formatted_transfer_scalar_write' at > > > /home/toon/compilers/gcc/libgfortran/io/transfer.c:2136:4: > > > /home/toon/compilers/gcc/libgfortran/io/write.c:1222:6: warning: writing > > > 1 byte into a region of size 0 [-Wstringop-overflow=] > > > 1222 | *q = '\0'; > > > | ^ > > > /home/toon/compilers/gcc/libgfortran/io/write.c: In function > > > 'formatted_transfer_scalar_write': > > > /home/toon/compilers/gcc/libgfortran/io/write.c:1291:8: note: at offset > > > [34, 4294967294] into destination object 'itoa_buf' of size 33 > > > 1291 | char itoa_buf[GFC_XTOA_BUF_SIZE]; > > > | ^ > > > > > > which was (of course) not given with a non-lto libgfortran. > > Yea. This certainly can happen with LTO. These warnings would > > definitely be something worth investigating. > > > > Essentially the inlining enabled by LTO can expose a different set of > > diagnostics. > > This particular place in libgfortran has > > /* write_z, which calls xtoa_big, is called from transfer.c, > formatted_transfer_scalar_write. There it is passed the kind as > argument, which means a maximum of 16. The buffer is large > enough, but the compiler does not know that, so shut up the > warning here. */ > #pragma GCC diagnostic push > #pragma GCC diagnostic ignored "-Wstringop-overflow" > *q = '\0'; > #pragma GCC diagnostic pop > > so obviously the #pragma doesn't survive through LTO. Somehow I think > this is a known bug, but maybe I misremember (I think we are not streaming > any of the ad-hoc location parts).
Yes it is a known bug. See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80922 . Thanks, Andrew > > Richard. > > > > > Jeff
